Heating device



Dec. 4, 1951 T. R. GNTHER 2,577,243

HEATING DEVICE Filed Dec. 27, 1948 lllllllllillllllllll||l 7f PatentedDec. 4, 1951 Torsten Ragnar Gnthe signor to Fritz Lundber r, Tranas,Sweden, asgs Skinnberederi & Fargeri Aktiebolag, Tranas, Sweden, acorporation of Sweden Application December 27, 1948, Serial No. 67,452In Sweden January 13, 1948 (Cl. 21S- 19) 2 Claims.

The present invention relates to electric heating devices, `andparticularly to such as are adapted to heat rotatable rolls of ironingmachines.

One object of my invention is to make provision for a more rapid heatingof a hollow cylindrical ironing roll than has hitherto been possiblewith rolls having electric heating-elements contacting the innerperipherie-al surface of the roll.

Another object of my invention is to prevent over-heating and consequentdamaging of the heating-resistors of heating elements for an ironingroll of the kind mentioned due to the comparatively slow heat transferassociated with such rolls having electric heating elements contactingthe inner peripherical surface of the roll.

Another object of my invention is to make provision in heating devicesfor hollow cylindrical ironing rolls, for permitting thermal extensionand contraction of the heating-resistors thereof in order to ascertain alonger life of the latter than has hitherto been possible with xedheating-resistors.

Other objects and advantages of my invention will be set forthhereinafter, reference being had to the accompanying diagrammaticdrawing in which:

Fig. 1 is a side-view of an ironer in accordance with my invention;

Fig. 2 is a cross-section on the line II-II in Fig. 1; and

Fig. 3 is a side-view of a resistance-helix associated with aninsulation-tube in accordance with this invention.

In the conventional heating-arrangement for the hollow cylindrical rollof an ironing machine for fur, the heating is accomplished by means ofheating-elements contacting the inner surface of the roll. On account ofthe comparatively low rate of heat transfer from such elements to theroll, the heating-resistors of such elements are liable to be overheatedand thus burnt down. Another disadvantage involved in such elementsconsists in that the heating-resistors are xedly positioned whereby nothermal expansion and contraction is permitted. This is a matter ofgreat importance for the durability of the heating-resistors.

The disadvantages indicated, according to the present invention, areavoided by disposing electric resistance-helices 4 (see Fig. 3) insertedin insulation-tubes 5 in longitudinal bores 3 (see Fig. 2) provided inthe roll I. For facilitating a larger scale along the electricconnection of either the heating-resistors 4 mutually with each other,or with the source of current S (see Fig. 1), it may be convenient toattach the ends (2) of the resistancehelices (4) to insulating plates 9perpendicular to the axis of the roll I and consisting of any suitableheat-resisting material, and provided with contact elements such asslip-rings I0 cooperating with brushes I I (Fig. l).

The invention, of course, should not be considered to be limited to theembodiment described and illustrated, as it is believed to be applicableto any kind of rotatable rolls required to be electrically heated.

What I claim and desire to secure by Letters Patent is:

l. A rotatable roll having an electric heating device, the peripheralportion of said roll having longitudinally extending bores therethrough,a heating resistor in the form of a helix, insulation tubes surroundingsaid resistor and said resistor having an external diameter less thanthe internal diameter of the insulation therearound whereby thermalexpansion and contraction of the helices is possible, said insulatedheating resistors being inserted in each said bore, said heatingresistors being entirely surrounded by and embedded in the material ofsaid roll to be heated. insulating plates arranged externally of saidroll and perpendicular to the axis thereof, slip rings constitutingcontact elements on said insulating plates, the ends of the heatingresistors being connected to said contact elements on said insulatingplates, and brushes for cooperation with said contact elements forconnecting the heating resistors to a source of current.

2. A rotatable roll having an electric heating device, the peripheralportion of said roll having a plurality of longitudinally extendingbores therethrough, insulating tubes inserted in said bores, a heatingresistor in the form of a helix slidingly disposed in each said tube insaid bores, said resistors having an external diameter less than theintern-al diameter of the insulating tubes whereby said resistors areenabled to change their length upon heating and cooling thereof withoutobstruction to such movements in said insulating tubes, said tubes beingentirely surrounded by the material of the roll to be heated.

TonsTEN RAGNAR GNTHER.

(References on following page) REFERENCES CITED The following referencesare of record in the Number le of this patent: 158,764 UNITED STATESPATENTS 5 Number Name Date 562867 415,856 Carpenter Nov. 26, 1889665,388 Benner Jan. 1, 1901 1,492,540 Karcher et a1. Apr. 29, 1924 10FOREIGN PAIEN TS Country Date Switzerland Feb. 1, 1933 France Mar. 5,1887 vFrance Mar.- 23, 1914 Great Britain July 19, 1941l

